One of the many operational difficulties in oil and gas exploration activities is the movement of drilling rigs between drilling locations. For example it may be determined that within a relatively small geographic area there are two or more possible drilling locations, and once ranked in order of likelihood of success a drilling rig might be set up to first drill on one location and if satisfactory results are not achieved then the rig might be moved to the next preferred adjacent location and a new well drilled with the hope of achieving better results.
Certain exploration activities may also require the drilling of more than one well in close proximity and again the locations of those wells might be relatively close together (as in only a number of feet or yards apart). For example with directional drilling it is possible to drill holes that extend laterally in different directions from a relatively small geographic area on the surface.
Where conventional drilling equipment is used, drilling of the typical well would start with the erection of the rig equipment over the well center and then the well could be drilled. The typical conventional drilling rig would include a substructure and derrick which would be erected into position such that the well could be drilled below the derrick at the well center. The rig and equipment would also include other supporting or service outbuildings or ancillary equipment or supply tanks or racks, all of which would need to be appropriately positioned around the main substructure in order to properly drill the well.
If it is at some point determined that satisfactory results are not being achieved at that particular drilling site, or if it is otherwise required within the site drilling plan, it may be necessary or desirable to move the rig to an adjacent drilling position, or an adjacent well center, and try to drill again. As outlined above, in many cases these adjacent well centers could be in relatively close proximity but regardless of the close proximity or location of the adjacent proposed well center, where a conventional drilling rig was being used it would be necessary to disassemble a large portion of the equipment, including potentially taking down the derrick and taking apart other pieces of the substructure, moving the substructure and supporting equipment to the new well center and reassembling the remainder of the equipment. This is obviously a time intensive process which results in a relatively long period of time being required to move the rig between drilling sites. Also, given the significant degree of disassembly which is required in this type of the movement, the wear and tear on the drilling equipment itself from its movement between sites is increased.
Another alternative type of equipment which has been designed to make it easier to move the drilling rig between adjacent drilling locations are various types of rigs which allow for the lifting of the rig using hydraulic legs or the like, to disengage the rig from the ground surface, and then physically pushing the rig to the new location using heavy equipment or the like. While this to some extent will alleviate the problems associated with complete or nearly complete disassembly of a drilling structure to move it between adjacent drilling locations, it creates its own set of problems. For example, where the rig itself is to be lifted and then pushed or dragged into a new location, it is necessary to minimize, or at the very least be cognizant of issues related to, the overall weight of the drilling substructure and any remaining attachments when it is to be moved. For example, it is not possible in this type of a movement arrangement to keep large quantities of pipe in the derrick while the unit is moved, since the substructure needs to be properly engineered to accommodate the weight. There are also concerns associated with the types of equipment needed to push the equipment between locations as well as proper weight distribution of the entire device onto a relatively small surface area such as the bottom of a series of lifters or feet which might be used to lift the rig structure off of the ground surface.
This method of lifting and moving a rig between drilling locations has been tried in the other types of equipment as well, for example it is known that in certain cases a set of rails or the like has been disposed beneath the rig. Again the rig needs to be lifted from the ground and then moved along the rails, and then set back down at the new location. Lifting of the rig limits the weight which can be moved, and introduces great stability, safety and equipment wear concerns. Another problem with a rail movement arrangement is that the rig can only be moved in one direction, that is in a single linear direction such as forward and back, while it cannot be moved from side to side. There are also similar weight distribution issues with this type of a movement arrangement.
It would be desirable to be able to provide an apparatus and method for the movement of a drilling rig between adjacent drilling locations that overcame the limitations of the use of conventional drilling equipment related to the difficulties in moving those rigs between adjacent drilling locations, and also to potentially address the issues which are associated with other current methods of movement of drilling rigs which are specifically manufactured for the purpose of movement between adjacent drilling locations by lifting them from the earth and moving them in some fashion either by rails or by pushing or pulling them using heavy equipment or built-in motor systems.